Understanding Heart Failure: Causes and Risks

• Heart failure involves impaired cardiac pumping or filling
• In heart failure, the heart cannot produce adequate cardiac output to meet the body's metabolic demands
• Heart failure is characterized by ventricular dysfunction, reduced exercise tolerance, diminished quality of life and shortened life expectancy

Etiology and Pathophysiology

• Primary risk factors for heart failure include coronary artery disease (CAD) and advancing age
• Contributing risk factors include hypertension, diabetes, tobacco use, obesity and high serum cholesterol

Heart Failure Causes

• Cardiac defects like myocardial infarction or valve deficiency can cause heart failure
• Defects outside the heart such as coronary artery disease, pulmonary hypertension or diabetes can cause heart failure

Pathophysiology

• Systolic failure is characterized by a decrease in the left ventricular ejection fraction (EF)
• Systolic failure can occur due to: impaired contractile function (e.g., MI), inability of heart to pump effectively, hypertension, cardiomyopathy and mechanical abnormalities
• Diastolic failure involves impaired ability of the ventricles to relax and fill during diastole which decreases CO
• Diastolic failure is diagnosed based on pulmonary congestion, pulmonary hypertension, ventricular hypertrophy, or normal EF
• Diastolic failure is caused by left ventricular hypertrophy from chronic hypertension, aortic stenosis and cardiomyopathies

Types of Heart Failure

• Right-sided heart failure symptoms include murmurs, jugular venous distention, edema, weight gain, ascites, anasarca and hepatomegaly
• Other symptoms of right-sided heart failure include fatigue, anxiety, right upper quadrant pain, anorexia and GI bloating, nausea
• Left-sided heart failure symptoms of acute decompensated heart failure (ADHF) include pulses alternans, increased HR and crackles
• Other symptoms include S3 and S4 heart sounds, pleural effusion, changes in mental status and restlessness and confusion
• Symptoms of left-sided heart failure also include weakness, fatigue, anxiety, depression, dyspnea, shallow respirations, orthopnea, dry hacking cough and nocturia

Clinical Manifestations of Acute Decompensated Heart Failure (ADHF)

• Physical findings include orthopnea, dyspnea/tachypnea, use of accessory muscles, and cool, clammy skin
• Additional physical findings include cough with frothy, blood-tinged sputum (pink), crackles, wheezes, rhonchi in breath sounds, tachycardia, hypotension or hypertension, and cyanosis (late sign)
• Pulmonary edema, often life-threatening, can manifest At first this may include an increase in the respiratory rate. and a decrease in PaO2 Later symptoms include tachypnea and respiratory acidosis

Pulmonary Edema

• Pulmonary edema inhibits oxygen and carbon dioxide exchange at the aveolar-capillary interface
• Increased pulmonary capillary hydrostatic pressure causes fluid to move from the vascular space into the pulmonary interstitial space
• Lymphatic flow increase in an attempt to pull fluid back into the vascular or lymphatic space, but can fail, causing a worsening of heart failure and a further movement of fluid into the interstitial space and into the alveoli

Chronic Heart Falure Clinical Manifestations

• Symptoms include fatigue, dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and a persistent, dry cough
• Additional symptoms include tachycardia, restlessness, confusion, decreased memory, chest pain (angina and dependent edema
• Edema may be pitting in nature and a sudden weight gain of >3 lb in 2 days may indicate an exacerbation of HF
• Other Symptoms include nocturia, dusky, cool, damp skin, shiny swollen lower extremities, diminished or absent hair growth and pigment changes

Complications of Heart Failure

• Pleural effusion (fluid retention in the pleural space)
• Atrial fibrillation (most common dysrhythmia), which promotes thrombus/embolus formation, increasing risk for stroke/PE
• High risk of fatal dysrhythmias (e.g., sudden cardiac death, ventricular tachycardia)
• Severe hepatomegaly, especially with RV failure and fibrosis and cirrhosis can develop over time due to fluid retention
• Renal insufficiency or failure is a common complication

Drug Therapy for Heart Failure

• Inotropic drugs influence the force of myocardial contraction
• Chronotropic drugs influence heart rate
• Dromotropic drugs influence conduction
• Medications used to treat heart muscle failure include: ACE inhibitors, angiotensin II receptor blockers, beta blockers, aldosterone antagonists, B-type natriuretic peptides, phosphodiesterase inhibitors, cardiac glycosides and loop diuretics

ACE Inhibitors

• It Prevents sodium and water reabsorption by inhibiting aldosterone secretion
• Results in diuresis, decreased preload, decreased blood volume, decreased blood return to the heart, decreased work of the heart
• Indicated for hypertension, heart failure, acute myocardial infarction
• Examples: lisinopril, enalapril, fosinopril, captopril, quinapril, ramipril, trandolapril and perindopril
• The most common side effect is a dry cough

Angiotensin II Receptor Blockers (ARBs)

• Potent vasodilators that decrease systemic vascular resistance (afterload)
• Can be used with diuretics in the treatment of hypertension or heart failure
• Examples: valsartan (Diovan), candesartan (Atacand), losartan (Cozaar)
• Side Effects: URI and hyperkalemia (less likely than with ACE inhibitors)

Beta Blockers

• Act by reducing or blocking sympathetic nervous system stimulation to the heart and the heart's conduction system
• Result in reduced heart rate, delayed AV node conduction, reduced myocardial contractility and decreased myocardial automaticity
• Examples: metoprolol and carvedilol (Coreg)
• Side effects include impotence and mental depression
• Exercise with caution with asthma (may cause bronchoconstriction) and diabetes (masks signs of hypoglycemia)

Aldosterone Antagonist

• Blocks aldosterone and promotes diuresis
• Used in severe stages of heart failure
• Spironolactone (Aldactone), a potassium-sparing diuretic, also acts as an aldosterone antagonist to reduce the symptoms of heart failure
• Eplerenone (Inspra) is a selective aldosterone blocker

B-type Natriuretic Peptides

• Have Vasodilating effects on arteries and veins and indirectly increases cardiac output
• Suppresses renin-angiotensin system and promotes diuresis
• Used in the treatment of life threatening heart failure with ICU with continuous IV infusion only
• Nesiritide (Natrecor) is the only drug in this class and is used in severe, life-threatening heart failure
• Notable adverse effects include hypotension dysrhythmia, headache and abdominal pain

Phosphodiesterase Inhibitors

• Act by inhibiting the enzyme phosphodiesterase
• Results in positive inotropic response (Increased force of heart contraction, squeeze of heart). Also promotes vasodilation
• Used for short-term management of heart failure (continuous IV infusion, ICU setting)
• Used when a patient does not respond to treatment with digoxin, diuretics, and/or vasodilators
• Example: milrinone (Primacor)

Phosphodiesterase Inhibitors: Adverse Effects

• The adverse effects of milrinone include: Ventricular dysrhythmias, hypotension, angina, hypokalemia, tremor, and thrombocytopenia

Cardiac Glycosides

• Oldest group of drugs, but no longer used as first-line treatment
• Originally obtained from Digitalis plant, foxglove
• Leads to decreased venous BP, vein engorgement, and increased coronary circulation
• Diuresis results from improved blood circulation
• Indications: Heart failure and Supraventricular dysrhythmias (Atrial fibrillation and atrial flutter)

Digoxin (Lanoxin)

• This medication slows conduction between the SA & AV node, and slows the rate in atrial fibrillation/flutter
• Given PO or IV
• Long half life and duration of action
• Follow Digoxin levels to determine dose (high risk for toxicity)
• Cardiac arrhythmymias, yellow halos as well for Adverse effects
• Digoxin Immune Fab (Digibind) as Antidote
• Inotrophic (force of Contraction); Chronotrophic (rate of contractions); Dromotrophic (electrical current)

Digoxin Cardiac Glycosides: Adverse Effects

• Has very narrow therapeutic window, thus drug levels must be monitored (0.5 to 2 ng/mL)
• Low potassium levels increase its toxicity
• Electrolyte levels must be monitored and kidneys must be working properly
• Side Effects: Cardiovascular, CNS, Eye, GI (anorexia, nausea, vomiting, diarrhea)
• Cardiovascular: dysrhythmias (bradycardia or tachycardia)
• CNS: headaches, fatigue, confusion, convulsions
• Eye: Colored vision (seeing green, yellow, purple), halos, flickering lights

Digoxin Toxicity

• This is treated with digoxin immune Fab (Digibind) therapy for life-threatening cardiac dysrhythmias or digoxin overdose
• Risk factors that predispose patients to Dig toxicity include: hypokalemia, use of cardiac pacemaker, Hepatic dysfunction, Hypercalcemia, Dysrhythmias and Advanced age

Loop Diuretics

• Includes furosemide, torsemide and bumetanide
• Manages edema associated with heart failure by decreasing plasma volume for the excretion of fluid, sodium and potassium
• Works well with decreased kidney function
• Decreases systemic vascular resistance, pulmonary vascular resistance, blood pressure, central venous pressure and left ventricular end diastolic pressure

Miscellaneous Drugs to Treat Heart Failure

• Hydralazine/isosorbide dinitrate (BiDil) which is a diuretic and influences contractility
• First drug approved for a specific ethnic group, namely African Americans
• Dobutamine's influence is contractility
• Beta1-selective vasoactive adrenergic drug, which is structurally similar to dopamine to improve squeeze of heart and frequency of heart rate

Heart Failure Drugs: Nursing Implications

• When administering nesiritide, milrinone, and dopamine, use an infusion pump
• Monitor I&O, heart rate and rhythm, BP, daily weights and respirations

Heart Failure Drugs: Nursing Implications (Cont'd)

• Assess clinical parameters, including weight, I&O measures, ECG and serum labs for potassium, sodium, magnesium, calcium, and renal and liver function
• Before giving any dose that influences HR, count apical pulse for 1 full minute
• If apical pulse less than 60 or greater than 100 beats/minute, hold dose and notify prescriber
• Hold dose and notify prescriber if patient experiences signs or symptoms of toxicity (visual disturbances like blurred vision, seeing green or yellow halos around objects)
• Avoid giving digoxin with high-fiber foods as fiber binds with digitalis.
• Immediately report a weight gain of 2 or more pounds in 1 day or 5 or more pounds in 1 week
• Monitor for therapeutic effects such as increased urinary output, decreased edema, shortness of breath, dyspnea, and crackles
• Also monitor for resolution of paroxysmal nocturnal dyspnea and improved peripheral pulses.
• Always monitor for adverse effects

SDOH

• SDOH factors associated with higher readmissions include the county in which the hospital is located
• SDOH include personal and social factors such as disability status, race, ethnicity, insurance, and income inequality
• Patients with heart failure who are food insecure, struggle with transportation, and have less access to medications or health services have poorer health outcomes
• SDOH influence an individual's physical, mental well-being and experience of care in the health system and community